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CVE-2026-105818

Status: Awaiting AnalysisMedium (5.9)—

Vault's PKI secrets engine ACME server did not restrict certificate identities that ACME challenges do not validate when issuing certificates under the default directory policy. This may allow an ACME client to obtain a certificate containing unverified identity claims, potentially enabling impersonation toward systems that trust certificates issued by the affected Vault PKI mount. This vulnerability (CVE-2026-105818) is fixed in Vault Community Edition 2.1.2, and Vault Enterprise 2.1.2, 1.21.12, 1.20.17, and 1.19.23.

CVSS

Exploitation probability (EPSS)

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

🎯 ATT&CK techniques

How this vulnerability is exploited and what the attacker gains, in MITRE ATT&CK terms.

Vector AV:N/PR:N permite explotación remota sin privilegios (T1190). Fallo de validación en ACME permite obtener certificados con identidades no verificadas, facilitando suplantación de identidad (T1078) y potencial manipulación de autoridades de confianza (T1556).

Inferred by our analysis agent from the official description, CVSS vector and CWE, and checked by a supervisor. May contain errors.

🛡️ ATT&CK mitigations that cover these techniques

Privileged Account ManagementUser Account ManagementPassword PoliciesMulti-factor AuthenticationApplication Developer GuidanceActive Directory Configuration

Affected technologies (1)

⚠ AI-inferred from the description — NVD hasn't analyzed this CVE yet, these aren't verified CPEs.

Hashicorp — VaultAI

CWEs

References

Raw JSON (NVD)

Show
{
  "id": "CVE-2026-105818",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-105818",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2026-10-08T17:06:48.843203Z"
        }
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "security@hashicorp.com",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 5.9,
          "attackVector": "NETWORK",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "HIGH",
          "availabilityImpact": "NONE",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 3.6,
        "exploitabilityScore": 2.2
      }
    ]
  },
  "affected": [
    {
      "source": "security@hashicorp.com",
      "affectedData": [
        {
          "repo": "https://github.com/hashicorp/vault",
          "vendor": "HashiCorp",
          "product": "Vault",
          "versions": [
            {
              "status": "affected",
              "version": "1.14.0",
              "lessThan": "2.1.2",
              "versionType": "semver"
            }
          ],
          "platforms": [
            "64 bit",
            "32 bit",
            "x86",
            "ARM",
            "MacOS",
            "Windows",
            "Linux"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://github.com/hashicorp/vault",
          "vendor": "HashiCorp",
          "product": "Vault Enterprise",
          "versions": [
            {
              "status": "affected",
              "changes": [
                {
                  "at": "1.21.12",
                  "status": "unaffected"
                },
                {
                  "at": "1.20.17",
                  "status": "unaffected"
                },
                {
                  "at": "1.19.23",
                  "status": "unaffected"
                }
              ],
              "version": "1.14.0",
              "lessThan": "2.1.2",
              "versionType": "semver"
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          ],
          "platforms": [
            "64 bit",
            "32 bit",
            "x86",
            "ARM",
            "MacOS",
            "Windows",
            "Linux"
          ],
          "defaultStatus": "unaffected"
        }
      ]
    }
  ],
  "published": "2026-10-07T22:17:02.843",
  "references": [
    {
      "url": "https://discuss.hashicorp.com/t/hcsec-2026-40-vault-pki-acme-default-directory-policy-may-issue-certificates-with-unverified-identities/77812",
      "source": "security@hashicorp.com"
    }
  ],
  "vulnStatus": "Awaiting Analysis",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "security@hashicorp.com",
      "description": [
        {
          "lang": "en",
          "value": "CWE-345"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "Vault's PKI secrets engine ACME server did not restrict certificate identities that ACME challenges do not validate when issuing certificates under the default directory policy. This may allow an ACME client to obtain a certificate containing unverified identity claims, potentially enabling impersonation toward systems that trust certificates issued by the affected Vault PKI mount. This vulnerability (CVE-2026-105818) is fixed in Vault Community Edition 2.1.2, and Vault Enterprise 2.1.2, 1.21.12, 1.20.17, and 1.19.23."
    }
  ],
  "lastModified": "2026-10-08T21:07:57.460",
  "sourceIdentifier": "security@hashicorp.com"
}